% File src/library/stats/man/predict.Rd
% Part of the R package, http://www.R-project.org
% Copyright 1995-2007 R Core Development Team
% Distributed under GPL 2 or later

\name{predict}
\title{Model Predictions}
\usage{
predict (object, \dots)
}
\alias{predict}
\arguments{
  \item{object}{a model object for which prediction is desired.}
  \item{\dots}{additional arguments affecting the predictions produced.}
}
\description{
  \code{predict} is a generic function for predictions from the results of
  various model fitting functions.  The function invokes particular
  \emph{methods} which depend on the \code{\link{class}} of
  the first argument.
}
\details{
  Most prediction methods which similar to fitting linear models have an
  argument \code{newdata} specifying the first place to look for
  explanatory variables to be used for prediction.
  Some considerable attempts are made to match up
  the columns in \code{newdata} to those used for fitting, for example
  that they are of comparable types and that any factors have the same
  level set in the same order (or can be transformed to be so).

  Time series prediction methods in package \pkg{stats} have an argument
  \code{n.ahead} specifying how many time steps ahead to predict.

  Many methods have a logical argument \code{se.fit} saying if standard
  errors are to returned.
}
 \value{
  The form of the value returned by \code{predict} depends on the
  class of its argument.  See the documentation of the
  particular methods for details of what is produced by that method.
}
\seealso{
  \code{\link{predict.glm}},
  \code{\link{predict.lm}},
  \code{\link{predict.loess}},
  \code{\link{predict.nls}},
  \code{\link{predict.poly}},
  \code{\link{predict.princomp}},
  \code{\link{predict.smooth.spline}}.

  For time-series prediction,
  \code{\link{predict.ar}},
  \code{\link{predict.Arima}},
  \code{\link{predict.arima0}},
  \code{\link{predict.HoltWinters}},
  \code{\link{predict.StructTS}}.
}
\references{
  Chambers, J. M. and Hastie, T. J. (1992)
  \emph{Statistical Models in S}.
  Wadsworth & Brooks/Cole.
}
\examples{
require(utils)

## All the "predict" methods found
## NB most of the methods in the standard packages are hidden.
for(fn in methods("predict"))
   try({
       f <- eval(substitute(getAnywhere(fn)$objs[[1]], list(fn = fn)))
       cat(fn, ":\n\t", deparse(args(f)), "\n")
       }, silent = TRUE)
}
\keyword{methods}
